SSCI transitions code sends a large number of small show rects
to the graphics manager, one at a time, for each division of a
transition. Each time a rect is submitted, a call to showBits
is made. This design was used when transitions for SCI32 were
first implemented in ScummVM, and it worked OK because the
hardware surface was updated by EventManager::getSciEvent,
not showBits, so the large number of calls to showBits from the
transitions code did not adversely affect engine performance.
Later in SCI32 engine development, hardware surface updates
were changed to occur in showBits so that the hardware surface
would be updated at frame-out time, instead of at input-in time.
This change meant that now the large number of calls to showBits
from transitions became very expensive, and the engine would
stall constantly refreshing the entire hardware surface.
To fix this problem, the transitions code now (1) maximises the
size of rects coming from transitions, when possible, and (2) only
calls showBits when all the rects from one frame of a transition
have been calculated and added to the show rects list.
Additionally, there were some arithmetic errors in the
implementation of pixel dissolve that have been corrected in this
changeset.
Fixes Trac#9614.
Memory references and integers in SSCI are both 16-bit numbers,
so game scripts frequently (incorrectly) use an IntArray instead
of an IDArray for holding references. Since references in ScummVM
are 32-bit reg_ts, IntArray entries must be large enough to hold
reg_ts in order to be compatible with game scripts that store
references in integer arrays.
The alternative solution is to find and patch all incorrect use of
IntArray across all games. This is possible, but a bit risky from
a save game stability perspective, since incorrect IntArray usage
is sometimes not apparent until well after the array is
instantiated (like GK1's global interview array).
This change invalidates existing SCI32 save games.
This fixes the incorrect appearance of the Sierra logo in PQ4 when
the main menu appears in hi-res mode.
The behaviour of kPalCycle(SetCycle) changed in between 2.1early
and 2.1mid to fix an off-by-one error that prevented the last
palette entry in a cycle range from being used. Some earlier games,
like PQ4CD in hi-res mode, relied on this behaviour, and would
render incorrectly if the last palette entry in a range was used.
This workaround may be able to be vastly simplified in the future
since, so far, simply returning the number of cels in loop 0 is
enough to make all the scripts with this bug work as expected.
Fixes Torin room 43000.
The algorithm in Graphics::drawThickLine2 for drawing thick lines
is not completely accurate and so there are still some single-pixel
rendering bugs, but these do not impact the game itself and can
be fixed separately.
This change invalidates earlier SCI32 save games, which separated
arrays and strings in an incompatible manner. Old save games
contain invalid references to a string segment which no longer
exists, and contain incompatible array structures that lack
critical type information.
The sleep values for video playback are the amount of time until
the next frame needs to be displayed, whereas speedThrottler is
used to ensure that a given amount of time always elapses between
two triggered speedThrottler calls.
Colin Snover
Eugene Sandulenko
Filippos Karapetis